Note: Since the merger of Wachovia and World Savings the Wachovia family of companies
no longer uses the original COSI index for new mortgages.
The original COSI index (a.k.a. GDW
COSI or World Savings COSI) has been discontinued. The final
COSI value {4.79} was released in September, 2007 for the month of August 2007.
Starting from August 1, 2007 Wachovia offers the new Wachovia Cost of Savings
Index.
In October 2008 Wachovia discontinued providing updates to the new Wachovia Cost of Savings Index rate to the public.
It is still being provided for existing customers though (until they are migrated over to a new
index).
Starting from January 1, 2009, our ability to report and
forecast the Wachovia Cost of Savings Index is limited.
The Wachovia Cost of Savings Index is a new mortgage (ARM) index available through World Savings, a Wachovia Company. The index is based on the interest
rates Wachovia pays to individuals on certificates of deposit (CDs), also known as 'personal time deposits'. The Wachovia COSI is calculated monthly and is
based on the weighted average of all the interest rates paid on certificates of deposit held by individual depositors as of the last business day of each month.

As personal time deposit rates tend to move more slowly than market interest rates in general, and because the W-COSI is composed of a portfolio of such
deposits with different maturities, the Wachovia Cost of Savings Index lags when market rates move up or down. Since the W-COSI is more steady than the other
popular indexes more closely tied to market interest rates, ARMs tied to this index are good for you if rates are rising (but not good if they are falling).

Wachovia Cost of Savings Index History

Month

COSI

2005 ~ Jan

2.81

2005 ~ Feb

2.87

2005 ~ Mar

2.95

2005 ~ Apr

3.03

2005 ~ May

3.10

2005 ~ Jun

3.15

2005 ~ Jul

3.25

2005 ~ Aug

3.34

2005 ~ Sep

3.43

2005 ~ Oct

3.49

2005 ~ Nov

3.56

2005 ~ Dec

3.64

2006 ~ Jan

3.74

2006 ~ Feb

3.82

2006 ~ Mar

3.91

2006 ~ Apr

4.01

2006 ~ May

4.13

2006 ~ Jun

4.24

2006 ~ Jul

4.38

2006 ~ Aug

4.54

2006 ~ Sep

4.65

2006 ~ Oct

4.74

2006 ~ Nov

4.80

2006 ~ Dec

4.85

2007 ~ Jan

4.88

2007 ~ Feb

4.91

2007 ~ Mar

4.92

2007 ~ Apr

4.94

2007 ~ May

4.91

2007 ~ Jun

4.90

2007 ~ Jul

4.90

2007 ~ Aug

4.85

2007 ~ Sep

4.88

2007 ~ Oct

4.90

2007 ~ Nov

4.85

2007 ~ Dec

4.79

2008 ~ Jan

4.74

2008 ~ Feb

4.65

2008 ~ Mar

4.43

2008 ~ Apr

4.19

2008 ~ May

3.91

2008 ~ Jun

3.74

Month

COSI

2008 ~ Jul

3.77

2008 ~ Aug

3.73

2008 ~ Sep

3.74

2008 ~ Oct

3.76

2008 ~ Nov

3.78

2008 ~ Dec

3.76

2009 ~ Jan

3.69

2009 ~ Feb

3.60

2009 ~ Mar

3.60

2009 ~ Apr

3.55

2009 ~ May

3.51

2009 ~ Jun

3.43

2009 ~ Jul

3.22

2009 ~ Aug

3.12

2009 ~ Sep

2.94

2009 ~ Oct

2.81

2009 ~ Nov

2.40

2009 ~ Dec

2.35

2010 ~ Jan

2.27

2010 ~ Feb

2.25

2010 ~ Mar

2.25

2010 ~ Apr

2.25

2010 ~ May

2.24

2010 ~ Jun

2.24

2010 ~ Jul

2.23

2010 ~ Aug

2.22

2010 ~ Sep

2.20

2010 ~ Oct

2.19

2010 ~ Nov

2.20

2010 ~ Dec

2.22

2011 ~ Jan

2.21

2011 ~ Feb

2.22

2011 ~ Mar

2.23

2011 ~ Apr

2.23

2011 ~ May

2.24

2011 ~ Jun

2.21

2011 ~ Jul

2.12

2011 ~ Aug

2.09

2011 ~ Sep

2.09

2011 ~ Oct

2.09

2011 ~ Nov

2.09

2011 ~ Dec

2.07

Month

COSI

2012 ~ Jan

2.06

2012 ~ Feb

2.05

2012 ~ Mar

2.01

2012 ~ Apr

1.97

2012 ~ May

1.94

2012 ~ Jun

1.91

2012 ~ Jul

1.89

2012 ~ Aug

1.89

2012 ~ Sep

1.89

2012 ~ Oct

1.89

2012 ~ Nov

1.89

2012 ~ Dec

1.88

2013 ~ Jan

1.88

2013 ~ Feb

1.88

2013 ~ Mar

1.86

2013 ~ Apr

1.82

2013 ~ May

1.70

2013 ~ Jun

1.56

2013 ~ Jul

1.44

2013 ~ Aug

1.33

2013 ~ Sep

1.16

2013 ~ Oct

1.07

2013 ~ Nov

0.99

2013 ~ Dec

0.96

2014 ~ Jan

0.94

2014 ~ Feb

0.93

2014 ~ Mar

0.91

2014 ~ Apr

0.90

2014 ~ May

0.90

2014 ~ Jun

0.90

2014 ~ Jul

0.89

2014 ~ Aug

0.89

2014 ~ Sep

0.85

2014 ~ Oct

0.85

2014 ~ Nov

0.84

2014 ~ Dec

0.84

2015 ~ Jan

0.83

2015 ~ Feb

0.78

2015 ~ Mar

0.73

2015 ~ Apr

0.69

2015 ~ May

0.65

Mortgage-X compiles historical values for the indexes which are widely used on adjustable rate mortgages (ARMs): Historical
Data

Mortgage Professionals Offering COSI-indexed Loans: If you are looking for a COSI-indexed ARM and need
more information or advice, we invite you to take advantage of our database of the most competitive lenders available. Just complete a short loan request form and the best lenders in your local area will contact you with
their rates and fees.